Processes for the production of hexafluoropropene and optionally other halogenated hydrocarbons containing fluorine

ABSTRACT

A process is disclosed for the manufacture of CF 3 CF═CF 2 , and optionally a least one compound selected from CF 3 CH 2 CF 3  and CF 3 CHFCHF 2 . The process involves contacting a reactor feed including a precursor stream of at least one halogenated propane of the formula CX 3 CH 2 CH y X (3−y)  and/or halogenated propene of the formula CX 3 CH═CH y X (2−y) , where each X is Cl or F and y is 0, 1 or 2 (provided that the average fluorine content of the precursor stream is no more than 5 fluorine substituents per molecule) with HF and Cl 2  in a chlorofluorination reaction zone containing a fluorination catalyst and operating at a temperature between about 150° C. and 400° C., to produce a reaction zone effluent including HF, HCl and a mixture of reaction products of the precursor feed which contains at least one compound of the formula C 3 Cl 2 F 6  including CClF 2 CClFCF 3  and at least one compound of the formula C 3 HClF 6 , including CHF 2 CClFCF 3  and has an average fluorine content which is at least one fluorine substituent per molecule more than the average fluorine content of the precursor stream. The chlorofluorination reaction zone effluent is distilled to produce (i) a low-boiling component including HCl (and when they are present in the reaction zone effluent, C 3 F 8 , C 3 ClF 7  and C 3 HF 7 ), (ii) a hydrogenation feed component containing at least one compo of the formula C 3 Cl 2 F 6  including CClF 2 CClFCF 3  and at least one compound of the formnula C 3 HClF 6  including CHF 2 CClFCF 3 , and an underfluorinated component including halogenated propanes containing at least one chlorine subtituent and from one to five fluorine substituents. The CClF 2 CClFCF 3  and CHF 2 CClFCF 3  of hydrogenation feed component (ii) is reacted with hydrogen to produce a mixture including CF 3 CF═CF 2  and CF 3 CHFCHF 2  and the CF 3 CF═CF 2  from this product mixture is recovered. Underfluorinated component (iii) is returned to the chlorofluorination reaction zone.

This application is a national filing under 35 USC 371 of InternationalApplication No. PCT/US99/12246 filed Jun. 2, 1999, claiming priority ofU.S. Provisional Application No. 60/087,751 filed Jun. 2, 1998.

FIELD OF THE INVENTION

The present invention relates to the synthesis of hexafluoropropene, andoptionally other halogenated hydrocarbons containing fluorine,especially 1,1,1,3,3,3-hexafluoropropane. and1,1,1,2,3,3-hexafluoropropane.

BACKGROUND

Commercial methods for the preparation of hexafluoropropene (CF₃CF═CF₂or HFP), a fluoromonomer, typically involve temperatures greater than600° C. The high reaction temperatures lead to the formation ofperfluoroisobutylene, an extremely toxic compound which is costly toremove and destroy (e.a., see European Patent Application No. 002,098).Processes for the manufacture of HFP at lower temperatures based on theuse of acyclic three-carbon hydrocarbons or partially halogenatedthree-carbon hydrocarbons are disclosed in U.S. Pat. Nos. 5,043,491,5,057,634 and 5,068,472.

1,1,1,2,3,3,3-Heptafluoropropane (CF₃CHFCF₃ or HFC-227ea), a fireextinguishant, can be prepared by the reaction of HF with HFP in contactwith activated carbon (e.g., see British Patent Specification No. GB902,590). The manufacture of HFC-227ea in this instance is tied to theavailability HFP.

U.S. Pat. No. 5.573.654 reports the preparation of1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃ or HFC-236fa), a fireextinguishant and refrigerant. by the reaction of extremely toxicperfluoroisobutylene with triethylamine and water.1,1,1,2,3,3-Hexafluoropropane (CF₃CHFCHF₂ or HFC-236ea) is also arefrigerant.

There is a need for alternative methods of manufacturing HFP and otherhalogenated hydrocarbons containing fluorine. such as the fluorinatedpropanes HFC-236fa and HFC-236ea.

SUMMARY OF THE INVENTION

This invention provides a process for the manufacture of CF₃CF═CF₂, andoptionally at least one compound selected from CF₃CH₂CF₃ and CF₃CHFCHF₂.The process comprises (a) contacting a reactor feed comprising aprecursor stream of at least one compound selected from halogenatedpropanes of the formula CX₃CH₂CH_(y)X_((3−y)) and halogenated propenesof the formula CX₃CH═CH_(y)X_((2−y)), where each X is independentlyselected from Cl and F and y is 0, 1 or 2, provided that the averagefluorine content of said precursor stream is no more than 5 fluorinesubstituents per molecule, with HF and Cl₂ in a chlorofluorinationreaction zone containing a fluorination catalyst and operating at atemperature between about 150° C. and 400° C. to produce a reaction zoneeffluent comprising HF, HCl and a mixture of reaction products of saidprecursor stream which contains at least one compound of the formulaC₃Cl₂F₆ including CClF₂CClFCF₃ and at least one compound of the formulaC₃HClF₆ including CHF₂CClFCF₃ and has an average fluorine content whichis at least one fluorine substituent per molecule more than the averagefluorine content of the precursor stream, (b) distilling the reactionzone effluent of (a) to produce (i) a low-boiling component comprisingHCl and when they are present in said reaction zone effluent, C₃F₈,C₃ClF₇ and C₃HF₇, (ii) a hydrogenation feed component comprising atleast one compound of the formula C₃Cl₂F₆ including CClF₂CCIFCF₃ and atleast one compound of the formula C₃HClF₆ including CHF₂CClFCF₃, and(iii) an underfluorinated component comprising halogenated propanescontaining at least one chlorine substituent and from one to fivefluorine substituents; (c) reacting the CClF₂CClFCF₃ and CHF₂CClFCF₃ ofhydrogenation feed component (ii) with hydrogen to produce a mixturecomprising CF₃CF═CF₂ and CF₃CHFCHF₂; (d) recovering the CF₃CF═CF. fromthe product mixture of (c); and (e) returning the underfluorinatedcomponent (iii) to the chlorofluorination reaction zone.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic flow diagram of an embodiment of the process ofthis invention.

DETAILED DESCRIPTION

The present invention provides a multi step process for the preparationof 1,1,1,2,3,3-hexafluoropropene, optionally together with1,1,1,3,3,3-hexafluoropropane, 1,1,1,2,3,3-hexafluoropropane, ormixtures thereof from readily available starting materials.

Suitable precursor stream compounds include the hydrochlorocarbonsCCl₃CH₂CH₂Cl, CCl₃CH₂CHCl₂ and CCl₃CH₂CCl₃. However, in certainembodiments of this invention. the precursor stream compounds of (a)(i.e., halogenated propanes of the formula CX₃CH₂CH_(y)X_((3−y)) andhalogenated propenes of the formula CX₃CH═CH_(y)X_((2−y))) can beprepared by reacting one or more of these hydrochlorocarbons (i.e.,compounds of the formula CCl₃CH₂CClZ₂, where Z is independently selectedfrom the group consisting of H and Cl) with substantially anhydrous HFin a reaction zone at a temperature of at least 80° C. but not more thanabout 250° C., to produce a reactor effluent comprising HF, HCl,CF₃CH═CZ₂, and CF₃CH₂CZ₂F where Z is as defined above. Suitablehydrochlorocarbons reactants for this fluorination include any ofCCl₃CH₂CH₂Cl, CCl₃CH₂CHCl₂, and CCl₃CH₂CCl₃. Thus, for example.CCl₃CH₂CH₂Cl can be reacted with HF to form CF₃CH═CH₂, and thefluorination product comprising CF₃CH═CH can be used as the precursorstream for (a). CCl₃CH₂CHCl₂ can be reacted with HF to form CF₃CH═CHCland the fluorination product comprising CF₃CH═CHCl can be used as theprecursor stream for (a). CCl₃CH₂CCl₃ can be reacted with HF to formCF₃CH═CCl₂ and CF₃CH₂CCl₂F and the fluorination product comprisingCF₃CH═CCl, and CF₃CH₂CCl₂F can be used as the precursor stream for (a).Of note are embodiments where the reactor effluent from thefluorination, comprising HCl, HF and the CF₃CH═CZ₂ compound(s), is fedto the chlorofluorination of (a).

The preparation of CCl₃CH₂CH₂Cl is described in U.S. Pat. No. 4,605.802.The preparation of CCl₃CH₂CHCl₂ and CCl₃CH₂CCl₃ is described inInternational Patent Application No. WO 97/05089.

The fluorination reaction may be carried out in the liquid or vaporphase. The contacting of CCl₃CH₂CClZ₂ with HF in the liquid phase may beconducted in one of several ways. The process of the invention may bedone in batch, semi-continuous. or continuous modes. In the batch mode.liquid CCl₃CH₂CClZ₂ and HF are combined in an autoclave or othersuitable reaction vessel and heated to the desired temperature.Preferably, the process of the invention is carried out by feedingliquid CCl₃CH₂CClZ₂ to a reactor containing HF. or a mixture containingHF and fluorinated compounds formed by heating CCl₃CH₂CClZ₂ and HF.Alternatively, HF may be fed to a reactor containing CCl₃CH₂CClZ₂, or amixture of CCl₃CH₂CClZ₂ and of fluorinated compounds formed by reactingHF and CCl₃CH₂CClZ₂. In a variation of this embodiment, both HF andCCl₃CH₂CClZ₂ may be fed concurrently in the desired stoichiometric ratioto a reactor containing a mixture of HF and fluorinated compounds formedby reacting HF and CCl₃CH₂CClZ₂.

Preferably, the reaction of HF with CCl₃CHCClZ₂ is carried out in thevapor phase in a heated tubular reactor. The reactor may be empty, butis preferably filled with a suitable packing such as Monel™ orHastelloy™ nickel alloy turnings or wool, or other material inert to HCland HF which allows efficient mixing of liquid CCl₃CH₂CClZ₂ and HFvapor. The CCl₃CH₂CClZ₂ feed rate is determined by the temperature andthe degree of fluorination desired.

Suitable temperatures for the fluorination reaction are within the rangeof from about 80° C. to about 250° C., preferably from about 100° C. toabout 200° C. Higher temperatures result in greater conversion of theCCl₃CH₂CClZ₂ and a greater degree of fluorination in the convertedproducts. The degree of fluorination reflects the number of fluorinesubstituents that replace chlorine substituents in the CCl₃CH₂CClZ₂starting material. For example, the product 3,3,3-trifluoro-1-propenerepresents a higher degree of fluorination than the product1,3-dichloro-1,1-difluoropropane.

The pressure used in the fluorination reaction is not critical and inbatch reactions is usually the autogenous pressure of the system at thereaction temperature. In a continuous process, typical reactor pressuresare from about 20 psig (239 kPa) to about 1.000 psig (6.994 kPa).

In the preferred, vapor phase mode of the fluorination reaction, thereaction may be carried out at atmospheric pressure, or for reasons suchas convenience of separations later in the process, pressures of up to30 atmospheres may be employed.

The mole ratio of HF to CCl₃CH₂CClZ₂ in the fluorination reaction istypically from about 3:1 to about 75:1, and is preferably from about 3:1to about 50:1. Ratios of about 8:1 to about 40:1 are most preferred asthis eliminates the need for further addition of HF in subsequentreaction steps.

Examples of compounds produced in the fluorination reaction includeCF₃CH═CH₂ (HFC-1243zf), CF₃CH₂CH₂F (HFC-254fb), CF₃CH═CHCl(HCFC-1233zd), CF₃CH₂CHClF (HCFC-244fa), CF₃CH═CCl₂ (HCFC-1223za) andCF₃CH₂CCl₂F (HCFC-234fb).

In addition, small amounts of other halogenated propanes may be formedhaving greater or lesser degrees of fluorination than the aforementionedproducts. Examples of products having a lower degree of fluorinationthan the aforementioned products include CF₃CH₂CH₂Cl (HCFC-253fb),CClF₂CH₂CH₂Cl (HCFC-252fb), CCl₂FCH₂CH₂Cl (HCFC-251fc), CC1F₂CH═CH₂(HCFC-1242zf), CF₃CH₂CHCl₂ (HCFC-243fa), CClF₂CH₂CHCl₂ (HCFC-242fa),CClF₂CH═CHCl (HCFC-1232zd), CF₃CH₂CCl₃ (HCFC-233fb), CClFH₂CHIClCF(HCFC-233fa), CClF₂CH₂CCl₃ (HCFC-232fb), CCl,FCH₂CCl₂F (HCFC-232fa),CClFCH₇CCl₃ (HCFC-231fa) and CClFCH═CClF (HCFC-1222zb).

Examples of compounds produced in the fluorination reaction having ahigher degree of fluorination than the aforementioned products includeCF₃CH═CHF (HFC-1234ze), CF₃CH₂CHF₂ (HFC-245fa), CF₃CH═CClF(HCFC-1224zb), CF₃CH═CF₂ (HFC-1225zc), CF₃CH)CClF₂ (HCFC-235fa), andCF₃CH₂CF₃ (HFC-236fa).

A fluorination catalyst is not needed for the reaction of HF withCCl₃CH₂CClZ₂, but may be added if desired to increase the conversion ofCCl₃CH₂CClZ₂, the rate of the reaction, or the degree of fluorination ofthe compounds produced. Liquid phase fluorination catalysts which may beused in the fluorination reaction include carbon, AlF₃, BF₃,FeCl_(3−a)F_(a) (where a is 0 to 3), FeZ₃ (where Z is Cl, F or mixturesthereof) supported on carbon, SbCl_(3−a)F_(a), AsF₃, MCl_(5−b)F_(b)(where b is 0 to 5 and M is Sb, Nb, Ta, or Mo), and M′Cl_(4−c)F_(c)(where c is 0 to 4, and M′ is Sn, Ti, Zr, or Hf).

Vapor phase fluorination catalysts which may be used in the fluorinationreaction include metal compounds (e.g., metal oxides. metal halides,and/or other metal salts). The metal compounds may be unsupported orsupported. Suitable supports for the supported catalyst include alumina,aluminum fluoride, fluorided alumina and carbon.

Suitable metal compounds for use as catalysts (optionally on alumina,aluminum fluoride, fluorided alumina, or carbon) include those ofchromium, iron, cobalt, nickel, manganese, magnesium, copper and zinc.Preferably when used on a support, the total metal content of thecatalyst will be from about 0.1 to 20 percent by weight; typically fromabout 0.1 to 10 percent by weight.

Of note are chromium-containing catalysts (e.g., Cr₂O₃ by itself or withother metal compounds such as magnesium halides or zinc halides onCr₂O₃); and mixtures of chromium-magnesium compounds (including metaloxides, metal halides. and/or other metal salts) optionally on graphite.

Fluorided alumina and aluminum fluoride can be prepared as described inU.S. Pat. No. 4,902,838. Metal compounds on aluminum fluoride and metalcompounds on fluorided alumina can be prepared by procedures describedin U.S. Pat. No. 4,766,260. Catalysts comprising chromium are well knownin the art (see e.g., U.S. Pat. No. 5.036,036). Chromium compoundssupported on alumina can be prepared as described in U.S. Pat. No.3.541,834. Chromium compounds supported on carbon can be prepared asdescribed in U.S. Pat. No. 3,632,834. Catalysts comprising chromium andmagnesium compounds may be prepared as described in Canadian Patent No.2,025,145. Other metal and magnesium compounds optionally on graphitecan be prepared in a similar manner to the latter patent.

Preferably. a catalyst is not used in the fluorination reaction. Ofparticular note are embodiments where CCl₃CH₂CH₂Cl is reacted with HF toform CF₃CH═CH₂ in a reactor which is free of added catalyst.

The feed to the chlorofluorination reaction zone includes the precursorstream as well as underfluorinated component (iii) from distillation(b).

In (a) of the process of the invention, the precursor stream of at leastone compound selected from halogenated propanes of the formulaCX₃CH₂CH_(y)X_((3−y)) and halogenated propenes of the formulaCX₃CH═CH_(y)X_((2−y)), where each X is independently selected from Cland F and y is 0, 1 or 2, provided that the average fluorine content ofsaid precursor stream is no more than 5 fluorine substituents permolecule, is contacted with HF and chlorine (Cl₂) in a reaction zone forchlorofluorination.

Preferably, the contacting in (a) is carried out in the vapor phase in aheated tubular reactor. Prior to the reactor, a mixing zone, preferablyfilled with a suitable packing such as Monel™ or Hastelloy™ nickel alloyturnings or wool, or other material inert to HCl and HF may be employedto allow efficient mixing of HF, HCl, CX₃CH₂CH_(y)X_((3−y)), andCX₃CH═CHyX_((2−y)) vapor with chlorine. The flow rates in said tubularreactor in the chlorofluorination reaction zone are determined by thetemperature and the degree of fluorination desired. A slower feed rateat a given temperature will increase contact time and tend to increasethe amount of conversion of CX₃CH₂CH_(y)X_((3−y)), andCX₃CH═CHYX_((2−y)) and the amount of fluorine incorporated into theproducts.

Suitable temperatures for the chlorofluorination are in the range offrom about 150° C. to about 400° C., preferably from about 200° C. toabout 325° C. Higher temperatures result in greater conversion ofCX₃CH₂CH_(y)X_((3−y)), and CX₃CH═CH_(y)X_((2−y)) and greater degrees offluorination and chlorination in the converted products. The degree ofchlorination reflects the number of chlorine substituents that replacehydrogen substituents in the starting materials. Said chlorinesubstituents themselves will be replaced by fluorine in thechlorofluorination reaction zone via the reaction of the chlorinatedproduct with HF. For example, the product1,1,2-trichloro-3,3,3-trifluoropropane (HCFC-233da) represents a higherdegree of chlorination than the intermediate1-chloro-3,3,3-trifluoro-1-propene (HCFC-12233zd).

Since the chlorofluorination reaction occurring in (a) is increasing thenet number of halogen (i.e. chlorine and fluorine) substituents in thepropane products, it is possible to refer to the degree of halogenationof the products which reflects the total number of chlorine and fluorinesubstituents that replace hydrogen substituents in the startingmaterial. Thus, the product 2-chloro-1,1,1,2,3.3-hexafluoropropane(HCFC-226ba) represents a higher degree of halogenation than theintermediate 1,2-dichloro-3,3,3-trifluoropropane (HCFC-243db).

The pressure of the chlorofluorination reaction is not critical and maybe in the range of from about 1 to about 30 atmospheres. A pressure ofabout 20 atmospheres may be advantageously employed to facilitateseparation of HCl from other reaction products in (b).

The mole ratio of HF to CX₃CH₂CH_(y)X_((3−y)), and/orCX₃CH═CH_(y)X_((2−y)) in the chlorofluorination reaction is typicallyfrom about 3:1 to about 75:1, and is preferably from about 3:1 to about50:1. Ratios of about 8:1 to about 40:1 are most preferred.

The ratio of Cl₂ to CX₃CH₂CH_(y)X_((3−y)), and/or CX₃CH═CH_(y)X_((2−y)),is typically from about 1:1 to about 10:1. The amount of chlorine fed tothe chlorofluorination reaction zone in (a) also depends on the hydrogencontent of the starting material is). If y is 0 in the above formulas, a1:1 ratio of Cl to the starting material(s) is sufficient for theprocess of the invention. If y is 2 in the above formulas, then a 3:1ratio of Cl₂ to the starting material(s) is sufficient for the processof the invention. A slight excess of chlorine over the stoichiometricamount may be necessary for practical reasons, but large excesses ofchlorine such as 20:1 will result in complete chlorofluorination of theproducts which is not necessary for the process of the invention.

Examples of compounds that may be produced in the chlorofluorinationreaction zone (a) include CF₃CClFCHF₂ (HCFC-226ba), CF₃CHFCClF,(HCFC-226ea), CF₃CF₂CHClF (HCFC-226ca), CF₃CHClCF₃ (HCFC-226da),CF₃CCl₂CF₃ (CFC-216aa), and CF₃CClFCClF₂ (CFC-216ba).

In addition, small amounts of other halogenated propanes may be formedhaving greater degrees of fluorination. Examples of halogenated propaneshaving greater degrees of fluorination are CF₃CClFCF₃ (CFC-217ba),CF₃CF₂CClF₂ (CFC-217ca), CF₃CHFCF₃ (HFC-227ea), CF₃CFCHF₂ (HFC-227ca)and CF₃CF₂CF₃ (FC-218).

In addition small amounts of other halogenated propanes may be formedhaving lower degrees of fluorination and chlorination. Examples ofproducts having lower degrees of fluorination and chlorination includeCF₃CCl₂CHF₂ (HCFC-225aa), CF₃CClFCHClF (HCFC-225ba), CF₃CF₂CHCl₂(HCFC-225ca), CF₃CHClCClF₂ (HCFC-225da), CF₃CHClCH₂Cl (HCFC-243db),CF₃CClCClF₂ (CFC-215aa), CClFCClFCClF₂ (CFC-215ba), CF₃CClFCCl₂F(CFC-215bb), CF₃CClCCl₂F (CFC-214ab), CF₃CCl₂CHClF (HCFC-224aa),CF₃CClFCHCl₂ (HCFC-224ba), CF₃CHClCCl₂F (HCFC-224db), CF₃CClFCH₂Cl(HCFC-234bb), CF₃CCl₂CH,₂Cl (HCFC-233ab), CF₃CHClCHCl₂ (HCFC-233da),CF₃CClCHCl₂ (HCFC-223aa), CF₃CHClCCl₃ (HCFC-223db) and CF₃CCl═CCl₂(CFC-1213xa).

Preferably the chlorofluorination reaction of (a) is done in thepresence of a fluorination catalyst. Examples of fluorination catalystssuitable for the chlorofluorination in (a) include those described abovein connection with CCl₃CH₂CClZ₂ fluorination reactions. Preferred vaporphase fluorination catalysts for (a) comprise trivalent chromium. Ofparticular note are Cr₂O₃ prepared by pyrolysis of (NH₄)₂Cr₂O₇, Cr₂O₃having a surface area greater than about 200 m²/g, and Cr₂O₃ prepared bypyrolysis of (NH₄)₂Cr₂O₇ or having a surface area greater than about 200m²/g which is pre-treated with a vaporizable fluorine-containingcompound such as HF or a fluorocarbon such as CCl₃F. These pre-treatedcatalysts are most preferred.

The Cr₂O₃ catalyst prepared by the pyrolysis of ammonium dichromatesuitable for (a) can be prepared by any method known to the artincluding those disclosed in U.S. Pat. Nos. 4,843,181 and 5,036,036which are hereby incorporated herein by reference. Other Cr₂O₃ catalystswhich may be used in (a) include catalysts having a surface area greaterthan about 200 m²/g, some of which are commercially available.

Generally, the resulting Cr₂O₃ will be pretreated with HF. Thispretreatment can be accomplished by placing Cr₂O₃ in a suitablecontainer which can be the reactor to be used to perform the reactiondescribed in (a) in the instant invention, and thereafter, passing HFover the dried Cr₂O₃ so as to partially saturate the Cr₂O₃ with HF. Thisis conveniently carried out by passing HF over the Cr₂O₃ for a period oftime, for example. about 15 to 300 minutes at a temperature of, forexample, about 200° C. to about 450° C. Nevertheless, this pretreamentis not essential.

In (b) of the process of the invention, the reaction zone effluent from(a) is distilled. Typically, more than one distillation column isemployed. The effluent from (a) is delivered to a distillation column toproduce a low-boiling component (i) comprising HCl and when they arepresent in the reaction zone effluent of (a) CF₃CF₂CF₃ (FC-218),CClF₂CF₂CF₃ (CFC-217ca), CF₃CClFCF₃ (CFC-217ba) CHF₂CF₂CF₃ (HFC-227ca)and CF₃CHFCF₃ (HFC-227ea). Any azeotropes of the above compounds withHCl or HF will also be in the low-boiling component.

It is noted that HFC-227ca and HFC-227ea are themselves valuable as fireextinguishants as disclosed in U.S. Pat. No. 5,084,190, and inrefrigeration and heat transfer compositions as disclosed in U.S. Pat.No. 5,417,871 and in International Application No. WO 95/08603.Accordingly, CFC-217ca and CFC-217ba from the low-boiling component (i)can be reacted with hydrogen after separation to produce additionalHFC-227ca and HFC-227ea respectively. The reaction of hydrogen withCFC-217ca and CFC-217ba is preferably carried out in the vapor phase ata temperature of at least about 100° C. and less than 500° C. over ametal-containing catalyst at a pressure of from about 100 kPa to about7,000 kPa. Preferred catalysts for the hydrogenolysis of the C—Cl bondsin CFC-217ca and CFC-217ba include those described for CClF₂CClFCF₃ andCHF₂CClFCF₃ hydrogenation herein.

A hydrogenation feed component (ii) is also produced from thedistillation process of (b). Components (ii) includes CClF₂CClFCF₃(CFC-216ba) and CHFICClFCF₃ (HCFC-226ba). Component (ii) also typicallyincludes HF and one or more of CF₃CHFCClF₂ (HCFC-226ea). CF₃CF₂CHClF(HCFC-226ca), and CF₃CCl₂CF₃ (CFC-216aa). It is normally preferable toadjust the chlorofluorination reaction temperatures such that theproduction of CF₃CClFCHF₂ and CF₃CClFCClF₂ is maximized. As illustratedin Examples 1 and 2, reaction temperatures above 300° C. can greatlyincrease the amount of CF₃CCl₂CF₃ and CF₃CF₂CHF that are formed at theexpense of HCFC-226ba and CFC-216ba. Accordingly, also of note areembodiments where the chlorofluorination of (a) produces CF₃CCl₂CF₃, andwhere the hydrogenation of (c) produces CF₃CH₂CF_(3.)

A third major fraction produced from the distillation (b) is anunderfluorinated component (iii) comprising halogenated propanescontaining at least one chlorine substituent and from one to fivefluorine substituents. Examples of compounds in component (iii) includeCF₃CCl₂CHF₂ (HCFC-225aa), CF₃CClFCHClF (HCFC-225ba), CF₃CF₂CHCl₂(HCFC-225ca), CF₃CHClCClF₂ (HCFC-225da), CF₃CHClCH₂Cl (HCFC-243db),CF₃CCl₂CClF₂ (CFC-215aa), CClF₂CClFCClF₂ (CFC-215ba), CF₃CClFCCl₂F(CFC-215bb), CF₃CClCCl₂F (CFC-214ab), CF₃CCl₂CHClF (HCFC-224aa),CF₃CClFCHCl₂ (HCFC-224ba), CF₃CHClCCl₂F (HCFC-224db), CF₃CClFCH₂Cl(HCFC-234bb), CF₃CCl₂CH₂Cl (HCFC-233ab), CF₃CHClCHCl₂ (HCFC-233da),CF₃CCl₂CHCl₂ (HCFC-223aa), CF₃CHClCCl₃ (HCFC-223db) and CF₃CCl═CCl₂(CFC-1213xa).

In (c) of the process of the invention, the hydrogenation feed component(ii) removed from the distillation column in (b) is reacted withhydrogen (H₂) in a reaction zone. The hydrogenation feed component (ii)can comprise a mixture of HF, CF₃CClFCHF₂ (HCFC-226ba), CF₃CHFCClF)(HCFC-226ea), CF₃CF₂CHClF (HCFC-226ca), CF₃CCl₂CF₃ (CFC-216aa), andCF₃CClFCClF₂ (CFC-216ba).

The reaction in (c) is carried out in the vapor phase. Suitabletemperatures for the reaction in (c) are in the range of from about 100°C. to about 400° C., preferably from about 150° C. to about 350° C.Higher temperatures result in greater conversion of CF₃CClFCHF₂(HCFC-226ba). CF₃CHFCClF₂ (HCFC-226ea), CF₃CF₂CHClF (HCFC-226ca),CF₃CCl₂CF₃ (CFC-216aa), and CF₃CClFCClF₂ (CFC-216ba).

The pressure used in (c) is not critical and may be in the range of fromabout 1 to 30 atmospheres. A pressure of about 20 atmospheres may beadvantageously employed to facilitate separation of HCl from otherreaction products.

The amount of hydrogen (H₂) fed to (c) is based on the total amount ofCF₃CClFCHF₂ (HCFC-226ba), CF₃CHFCClF₂ (HCFC-226ea), CF₃CF₂CHClF(HCFC-226ca). CF₃CCl₂CF₃ (CFC-216aa), and CF₃CClFCClF₂ (CFC-216ba) fedto the reaction zone. The ratio of H₂ to CF₃CClFCHF₂ (HCFC-226ba),CF₃CHFCClF₂ (HCFC-226ea), CF₃CF₂CHClF (HCFC-226ca), CF₃CCl₂CF₃(CFC-216aa). and CF₃CClFCClF₂ (CFC-216ba) is typically in the range offrom about 1:1 to about 20:1, preferably from about 2:1 to about 10:1.

Compounds produced in the reaction zone in step (c) ordinarily includeCF₃CF═CF₂ (HFP) and CF₃CH₂CF₃ (HFC-236fa). In addition, small amounts ofCF₃CHFCHF₂ (HFC-236ea), CF₃CFCH₂F (HFC-236cb) and CF₃CHClCF₃(HCFC-226da) will typically be formed.

Preferably the reaction in (c) takes place in the presence of acatalyst. Suitable catalysts for (c) include iron, rhenium, ruthenium,osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum. Saidcatalysts are preferably supported on carbon, a metal oxide such asalumina or chromia, fluorided alumina or a metal halide such as AlF₃,CrF₃ or MgF₂. Preparation of carbon-supported palladium catalysts aredescribed in U.S. Pat. No. 5,523,501.

Especially preferred catalysts for (c) are those containing rheniumand/or ruthenium. The catalysts containing rhenium and/or ruthenium mayor may not be supported. Preferred supports are carbon, alumina,aluminum fluoride and fluorided alumina. Preparation of supportedrhenium catalysts are described in U.S. Pat. No. 5,068,473. Particularruthenium-containing catalysts are disclosed in PCT InternationalPublication No. WO 97/19751.

In (d) of the process of the invention, CF₃CF═CF₂ produced in step (c),is recovered. Optionally, CF₃CH₂CF₃ (HFC-236fa), and CF₃CHFCHF₂(HFC-236ea) may also be recovered. These compounds are typicallyrecovered by distillation individually or as their HF azeotropes. HF maybe removed from these compounds by conventional means such as scrubbingwith base or by azeotropic distillation.

In (e) of the process of the invention, the underfluorinated component(iii) of (b) is returned to (a) for furter chlorofluorination.

FIG. 1 is illustrative of one method of practicing this invention.Referring to FIG. 1. a feed mixture comprising HF and CCl₃CH₂CClZ₂,where each Z is independently selected from the group H and Cl, andwhere the mole ratio of HF:CCl₃CH₂CClZ₂ is about 3:1 or more, is passedthrough line (110) into reactor (100). The reaction temperature is atleast 80° C. but not more than 250° C.

The reactor effluent from fluorination reactor (100) comprising HF, HCl,CF₃CH═CZ₂, and CF₃CH₂CZ₂F is passed through line (120) into line (420)where it is combined with the column bottoms from distillation column(400). The column (400) bottoms comprise C₃Z_(3+z)F_(5−z) where z is 0,1 or 2. Examples of compounds having the formula C₃Z_(3+z)F_(5−z)include CF₃CCl₂CHF₂ (HCFC-225aa), CF₃CClFCHClF (HCFC-225ba), CF₃CF₂CHCl₂(HCFC-225ca), CF₃CHClCClF₂ (HCFC-225da), CF₃CHClCH₂Cl (HCFC-243db),CF₃CCl₂CClF₂ (CFC-215aa), CClF₂CClFCClF₂ (CFC-215ba), CF₃CClFCCl₂F(CFC-215bb), CF₃CClCClF (HCFC-214ab), CF₃CCl₂CHClF (HCFC-224aa),CF₃CClFCHCl₂ (HCFC-224ba), CF₃CHClCCl₂F HCFC-224db), CF₃CClFCH₂Cl(HCFC-234bb), CF₃CCl.CH)Cl (HCFC-233ab). CF₃CHClCHCl₂ (HCFC-233da),CF₃CCl₂CHCl₂ (HCFC-223aa) and CF₃CHClCCl₃ (HCFC-223db).

The combined reactor (100) effluent and distillation column (400)bottoms are sent to reactor (200) which is maintained at a temperaturewithin the range of about 150° C. to about 350° C. Reactor (200) ispacked with a fluorination catalyst. A preferred catalyst is Cr₂O₃prepared by the pyrolysis of (NH₄)₂Cr₂O₇ as described in U.S. Pat. No.5,036,036. Chlorine is fed into the reactor (200) through line (210).The amount of chlorine fed to reactor (200) is based on the amount ofCCl₃CH₂CClX₂ fed to reactor (100) and the amount of C₃Z_(3+z)F_(5−z)recycled. The mole ratio of Cl₂:CCl₃CH₂CClX₂ is within the range ofabout 1:1 to about 10:1. Additional HF may be added. if required.

The chlorofluorination reactor (200) effluent comprising HF, HCl,CF₃CClFCHF₂, CF₃CHFCClF₂, CF₃CClFCClF₂, CF₃CCl₂CF₃, and a mixture ofC₃ZF₇ and C₃Z_(3+z)F_(5−z) where z is 0, 1 or 2, is sent through line(220) into distillation column (300). HCl, C₃HF₇, C₃ClF₇, C₃F₈ and anyazeotropes of HCl or HF with C₃HF₇, C₃ClF₇ or C₃F₈ are removed throughline (320) from the reactor (200) effluent and the remaining componentsof the reactor (200) effluent is sent through line (310) into a seconddistillation column (400).

HF, CF₃CClFCHF₂, CF₃CHFCClF₂, CF₃CClFCClF₂, and CF₃CCl₂CF₃ are removedfrom the top of column (400) through line (410) and sent to reactor(500) along with hydrogen, which is fed through line (510). The reactor(500) product is removed through line (520) and comprises. HCl, HF,hexafluoropropylene (i.e., CF₃CF═CF₂ or HFP),1,1,1,3,3,3-hexafluoropropane (CF₃CH₂CF₃ or HFC-236fa) and1,1,2,3,3,3-hexafluoropropane (HFC-236ea). HFP, HFC-236fa and HFC-236eacan be isolated by conventional means. The bottom fraction from column(400) which comprises C₃Z_(3+z)F_(5−z) where z is as defined above issent through line (420) into reactor (200).

Those skilled in the art will recognize that since the drawings arerepresentational. it will be necessary to include further items ofequipment in an actual commercial plant. such as pressure andtemperature sensors, pressure relief and control valves. compressors,pumps, storage tanks and the like. The provision of such ancillary itemsof equipment would be in accordance with conventional chemicalengineering practice.

The reactors used for this process and their associated feed lines.effluent lines. and other associated units should be constructed ofmaterials resistant to hydrogen fluoride and hydrogen chloride. Typicalmaterials of construction, well-known to the fluorination art, includestainless steels. in particular of the austenitic type. the well-knownhigh nickel alloys. such as Monel T nickel-copper alloys. Hastelloy™nickel-based alloys and Inconel™ nickel-cliromium alloys, andcopper-clad steel.

Without further elaboration it is believed that one skilled in the artcan, using the description herein. utilize the present invention to itsfullest extent. The following embodiments are, therefore, to beconstrued as merely illustrative, and do not constrain the remainder ofthe disclosure in any way whatsoever.

LEGEND 114a is CCl₂FCF₃ 115 is CClF₂CF₃ 214ab is CCl₂FCCl₂CF₃ 215aa isCClF₂CCl₂CF₃ 215ba is CClF₂CClFCClF₂ 215bb is CCl₂FCClFCF₃216aa-is-CF₃CCl₂CF₃ 216ba is CClF₂CClFCF₃ 216ca is CClF₂CF₂CClF₂ 216cbis CF₃CF₂CCl₂F 217ba is CF₃CClFCF₃ 217ca is CClF₂CF₂CF₃ 218 is CF₃CF₂CF₃223aa is CF₃CCl₂CHCl₂ 224aa is CF₃CCl₂CHClF 224ba is CF₃CClFCHCl₂ 225aais CHF₂Cl₂CF₃ 225ba is CHClFCClFCF₃ 225ca is CHCl₂CF₂CF₃ 226ba isCF₃CClFCHF₂ 226ca is CF₃CF₂CHClF 226da is CF₃CHClCF₃ 226ea isCClF₂CHFCF₃ 227ca is CF₃CF₂CHF₂ 227ea is CF₃CHFCF₃ 232 is C₃H₂Cl₄F₂233ab is CF₃CCl₂CH₂Cl 233da is CF₃CHClCHCl₂ 234 is C₃H₂Cl₂F₄ 234bb isCF₃CClFCH₂Cl 234da is CF₃CHClCHClF 235cb is CF₃CF₂CH₂Cl 235da isCF₃CHClCHF₂ 236fa is CF₃CH₂CF₃ 242 is C₃H₃Cl₃F₂ 243db is CF₃CHClCH₂Cl244 is C₃H₃ClF₄ 245fa is CF₃CH₂CHF₂ 252 is C₃H₄Cl₂F₂ 1213xa isCCl₂═CClCF₃ 1214 is C₃Cl₂F₄ 1215 is C₃ClF₅ 1222 is C₃HCl₃F₂ 1223 isC₃HCl₂F 1224 is C₃HClF₄ 1231 is C₃H₂Cl₃F 1232 is C₃H₂Cl₂F₂ 1233xf isCH₂═CClCF₃ 1233zd is CHCl═CHCF₃ 1234 is C₃H₂F₄ 1234ye is CHF═CFCHF₂1234ze is CHF═CHCF₃ 1243 is C₃H₃F₃ 1243zf is CH₂═CHCF₃ CT is contacttime

General Procedure for Product Analysis

The following general procedure is illustrative of the method used. Partof the total reactor effluent was sampled on-line for organic productanalysis using a Hewlett Packard HP 5890 gas chromatograph equipped witha 20 ft. (6.1 m) long×⅛ in. (0.32 cm) diameter tubing containing Krytox®perfluorinated polyether on an inert carbon support. The helium flow was30 mL/min. Gas chromatographic conditions were 60° C. for an initialhold period of three minutes followed by temperature programming to 200°C. at a rate of 6° C./minute.

The bulk of the reactor effluent containing organic products and alsoinorganic acids such as HCl and HF was treated with aqueous causticprior to disposal.

EXAMPLE 1 Chlorofluorination of CCl₃CH₂CH₂Cl

Chromium oxide (40.0 g, 30 mL, −12 to +20 mesh, (1.68 to 0.84 mm)),obtained from the pyrolysis of ammonium dichromate prepared according tothe procedure described in U.S. Pat. No. 5,036,036, was placed in a ⅝″(1.58 cm) diameter Inconel™ nickel alloy reactor tube heated in afluidized sand bath. The catalyst was heated from 60° C. to 175° C. in aflow of nitrogen (50 cc/min) over the course of about one hour. HF wasthen admitted to the reactor at a flow rate of 50 cc/min. After 35minutes. the nitrogen flow was decreased to 20 cc/min and the HF flowincreased to 80 cc/min. The reactor temperature was gradually increasedto 400° C. during a three hour period and maintained at 400° C. for anadditional 55 minutes. At the end of this period, the HF flow wasstopped and the reactor cooled to 250° C. under 20 sccm (3.3×10⁻⁷ m³/s)nitrogen flow.

The results of the chlorofluorination of CCl₃CH₂CH₂Cl are shown in Table1; analytical data is given in units of GC area %. Total gas flow in thereactor was 120 sccm (2.0×10⁻⁶ m³/s) for a 15 second contact time exceptfor the data at 400° C. which was conducted with a 30 second contacttime.

TABLE 1 T Molar Ratio C.T. % % % % % % % ° C. HF:250fb:Cl₂ Sec. 1243zf242 243db 244** 234bb 224aa 224ba 170 20:1:0 nc 97.5 0 0 0.1 0 0 0 20030:1:6 nc 35.4 4.2 34.9 2.6 0 0 0 200 30:1:6 15 0.1 0 55.3 7.1 6.7* 4.20 225 30:1:6 15 0 0 10.6 3.I 19.0 20.0 0 250 30:1:6 15 0 0 0 0 0.8 31.725.3 275 30:1:6 15 0 0 0 0 0 3.1 4.6 300 30:1:6 15 0 0 0 0 0 0.5 0.7 32530:1:6 15 0 0 0 0 0 0.3 0.3 350 30:1:6 15 0 0 0 0 0 0 0 375 30:1:6 15 00 0 0 0 0 0 400 30:1:6 30 0 0 0 0 0 0 0 nc = no catalyst; reactantsmixed in tube packed with Monel gauze (not exposed to the fluorinationcatalyst) *Includes 1.7% of unidentified isomer *Sum of two isomers T %% % % % % % % % ° C. 1233zd 1233xf 233ab 223aa 1213xa 1214* 215aa**225aa 225ba 170 0 0 0 0 0 0 0 0 0 200 4.6 4.0 3.2 2.5 0 0 0 0 0 200 5.81.5 10.7 0.5 2.4 0 0 0.1 0 225 1.3 0.4 32.0 2.1 6.8 0 0 0.4 0.5 250 0.10.1 0.3 0 6.5 4.3 2.8 7.1 18.8 275 0 0 0 0 0.5 0.2 7.0 37.3 18.7 300 0 00 0 0.1 0 7.4 26.3 3.3 325 0 0 0 0 0.1 0 8.9 5.2 1.2 350 0 0 0 0 0 0 0.81.1 0.2 375 0 0 0 0 0 0 0.9 0.6 0.2 400 0 0 0 0 0 0 0.2 0.2 0 *sum oftwo isomers *includes <1% of an unidentified isomer T % % % % % % % % %° C. 225ca 226ba 226ca 216ba 216aa 217ba 217ca 227ca 218 170 0 0 0 0 0 00 0 0 200 0 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 0 0 225 0 0 0 0 0 0 0 0 0250 0 0.6 0 0.1 0.2 0 0 0 0 275 4.2 14.7 4.4 1.7 1.2 0.1 0 0.4 0 300 3.431.2 7.7 2.4 4.4 0.5 1.1 9.0 0 325 3.3 24.3 5.3 3.8 16.1 1.1 3.8 24.5 0350 0.9 10.7 3.4 3.2 25.2 6.1 7.4 39.4 0.4 375 1.6 2.1 3.3 2.9 45.5 7.612.9 19.9 1.2 400 0.4 0.9 1.3 0.8 59.4 15.0 6.4 9.7 4.7 Other compoundsobserved at low levels include: 216cb, 226da, 232, 235cb, 245fa, 252,1222, 1223, 1232, 1234ye, 1234ze.

EXAMPLE 2 Chlorofluorination of CCl₃CH₂CHCl₂

A fresh charge of chromium oxide (40.0 g, 30 mL, −12 to +20 mesh, (1.68to 0.84 mm)) was loaded in the reactor and activated with HF followingthe procedure described in Example 1.

The results of the chlorofluorination of CCl₃CH₂CHCl₂ are shown in Table2; analytical data is given in units of GC area %. Total gas flow in thereactor was 120 sccm (2.0×10⁻⁶ m³/s) for a 15 second contact time exceptfor the data at 400° C. which was conducted with a 30 second contacttime.

TABLE 2 T Molar Ratio C.T. % % % % % % % ° C. HF:240fa:Cl₂ Sec. 1234*1243 242 244 234da* 224aa 224ba 200 20:1:0 nc 2.7 0.1 0.2 0.3 0 0 0 20030:1:6 nc 4.5 0 4.2 2.6 1.4 0 0 225 30:1:6 15 0 0 0 0 0 47.4 22.0 25030:1:6 15 0 0 0 0 0 21.1 23.8 275 30:1:6 15 0 0 0 0 0 1.6 2.6 300 30:1:615 0 0 0 0 0 0.4 0.6 325 30:1:6 15 0 0 0 0 0 0.2 0.3 350 30:1:6 15 0 0 00 0 0.06 0.09 375 30:1:6 15 0 0 0 0 0 0 0 400 30:1:6 30 0 0 0 0 0 0 0 T% % % % % % % % ° C. 1223* 1233zd* 233da 223aa 1224* 235da 1213xa 1214200 0 96.6 0 0 0 0 0 0 200 6.6 77.0 8.0 0 0 0 0 0 225 1.8 0 0 4.5 0.9513.0 0.3 0 250 0 0 0 0.7 1.0 2.0 0 1.3 275 0 0 0 0 0.1 0 0 0 300 0 0 0 00.2 0 0 0 325 0 0 0 0 0 0 0 0 350 0 0 0 0 0 0 0 0 375 0 0 0 0 0 0 0 0400 0 0 0 0 0 0 0 0 T % % % % % % % % ° C. 214ab 215ba/bb 215aa 225aa225ba* 225ca 216ca/cb 226da 200 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 0 0 2250.3 0.3 0.9 4.6 2.6 0 0 0 250 0 1.0 2.8 14.8 28.7 0 0 0 275 0 0.2 6.042.3 13.8 3.8 0.5 0.3 300 0 0 6.8 24.4 3.2 2.4 0.6 0.6 325 0 0 8.4 5.11.1 2.2 0.5 0.5 350 0 0 2.0 1.4 0.4 1.7 0.4 0.1 375 0 0 0.02 0.08 0 00.1 0.03 400 0 0 0.2 0 0 0.06 0.2 0 T % % % % % % % % ° C. 226ba 226ca216ba 216aa 217ba 217ca 227ca 218 200 0 0 0 0 0 0 0 0 200 0 0 0 0 0 0 00 225 0 0 0 0 0 0 0 0 250 1.4 0.09 0.4 0.3 0 0 0 0 275 17.9 5.9 2.2 1.50.1 0.08 0.7 0 300 33.8 6.7 2.7 5.1 0.4 1.2 10.3 0 325 26.1 4.8 4.1 16.60.97 3.9 24.7 0.04 350 7.8 4.3 4.4 32.5 3.5 8.5 32.1 0.3 375 5.4 0.5 2.235.1 11.6 9.6 32.6 1.8 400 0.2 0.2 0.8 64.4 16.7 9.1 1.6 6.2 nc = nocatalyst; reactants mixed in tube packed with Monel gauze (not exposedto the fluorination catalyst) *sum of two isomers Other compoundsobserved at low levels include: 114a, 115, 236fa, 1215, 1231

What is claimed is:
 1. A process for the manufacture of CF₃CF═CF₂, andoptionally at least one compound selected from CF₃CH₂CF₃ and CF₃CHFCHF₂,comprising: (a) contacting a reactor feed comprising precursor stream ofat least one compound selected from halogenated propanes of the formulaCX₃CH₂CH_(y)X_((3−y)) and halogenated propenes of the formulaCX₃CH═CH_(y)X_((2−y)), where each X is independently selected from Cland F and y is 0, 1 or 2, provided that the average fluorine content ofsaid precursor stream is no more than 5 fluorine substituents permolecule, with HF and Cl₂ in a chlorofluorination reaction zonecontaining a fluorination catalyst and operating at a temperaturebetween about 150° C. and 400° C. to produce a reaction zone effluentcomprising HF, HCl and a mixture of reaction products of said precursorstream which contains at least one compound of the formula C₃Cl₂F₆including CClF₂CClFCF₃ and at least one compound of the formula C₃HClF₆including CHF₂CClFCF₃ and has an average fluorine content which is atleast one fluorine substituent per molecule more than the averagefluorine content of the precursor stream; (b) distilling the reactionzone effluent of (a) to produce (i) a low-boiling component comprisingHCl and when they are present in said reaction zone effluent, C₃F₈,C₃ClF₇ and C₃HF₇, (ii) a hydrogenation feed component comprising atleast one compound of the formula C₃Cl₂F₆ including CClF₂CClFCF₃ and atleast one compound of the formula C₃HClF₆ including CHF₂CClFCF₃, and(iii) an underfluorinated component comprising halogenated propanescontaining at least one chlorine substituent and from one to fivefluorine substituents; (c) reacting the CClF₂CClFCF₃ and CHF₂CClFCF₃ ofhydrogenation feed component (ii) with hydrogen to produce a mixturecomprising CF₃CF═CF₂ and CF₃CHFCHF₂; (d) recovering the CF₃CF═CF₂ fromthe product mixture of (c); and (e) returning the underfluorinatedcomponent (iii) to the chlorofluorination reaction zone.
 2. The processof claim 1 wherein CCl₃CH₂CH₂Cl is reacted with HF to form CF₃CH═CH₂,and the fluorination product comprising CF₃CH═CH₂ is used as theprecursor stream for (a).
 3. The process of claim 2 wherein theCCl₃CH₂CH₂Cl is reacted in a reactor which is free of added catalyst. 4.The process of claim 1 wherein CCl₃CH₂CHCl₂ is reacted with HF to formCF₃CH═CHCl, and the fluorination product comprising CF₃CH═CHCl is usedas the precursor stream for (a).
 5. The process of claim 1 whereinCCl₃CH₂CCl₃ is reacted with HF to form CF₃CH═CCl₂ and CF₃CH₂CCl₂F andthe fluorination product comprising CF₃CH═CCl₂ and CF₃CH₂CCl₂F is usedas the precursor stream for (a).
 6. The process of claim 1 whereinCF₃CCl₂CF₃ is produced in (a), and CF₃CH₂CF₃ is produced in (c).
 7. Theprocess of claim 1 wherein the catalyst of (a) comprises trivalentchromium.
 8. The process of claim 1 wherein the reaction of (c) isconducted in the presence of a catalyst containing at least one ofrhenium and ruthenium.
 9. A process for the manufacture of CF₃CF═CF₂,and optionally at least one compound selected from CF₃CH₂CF₃ andCF₃CHFCHF₂, comprising: (a) contacting a reactor feed comprisingprecursor stream of at least one compound selected from halogenatedpropanes of the formula CX₃CH₂CH_(y)X_((3−y)) and halogenated propenesof the formula CX₃CH═C_(y)X_((2−y)), where each X is independentlyselected from Cl and F and y is 0, 1 or 2, provided that the averagefluorine content of said precursor stream is no more than 5 fluorinesubstituents per molecule, with HF and Cl₂ in a chlorofluorinationreaction zone containing a fluorination catalyst and operating at atemperature between about 150° C. and 325° C., to produce a reactionzone effluent comprising HF, HCl and a mixture of reaction products ofsaid precursor stream which contains at least one compound of theformula C₃Cl₂F₆ including CClF₂CClFCF₃ and at least one compound of theformula C₃HClF₆ including CHF₂CClFCF₃ and has an average fluorinecontent which is at least one fluorine substituent per molecule morethan the average fluorine content of the precursor stream; (b)distilling the reaction zone effluent of (a) to produce (i) alow-boiling component comprising HCl and when they are present in saidreaction zone effluent, C₃F₈, C₃ClF₇ and C₃HF₇, (ii) a hydrogenationfeed component comprising at least one compound of the formula C₃Cl₂F₆including CClF₂CClFCF₃ and at least one compound of the formula C₃HClF₆including CHF₂CClFCF₃, and (iii) an underfluorinated componentcomprising halogenated propanes containing at least one chlorinesubstituent and from one to five fluorine substituents; (c) reacting theCClF₂CClFCF₃ and CHF₂CClFCF₃ of hydrogenation feed component (ii) withhydrogen to produce a mixture comprising CF₃CF═CF₂ and CF₃CHFCHF₂; (d)recovering the CF₃CF═CF₂ from the product mixture of (c); and (e)returning the underfluorinated component (iii) to the chlorofluorinationreaction zone.
 10. The process of claim 9 wherein CCl₃CH₂CH₂Cl isreacted with HF to form CF₃CH═CH₂, and the fluorination productcomprising CF₃CH═CH₂ is used as the precursor stream for (a).
 11. Theprocess of claim 10 wherein the CCl₃CH₂CH₂Cl is reacted in a reactorwhich is free of added catalyst.
 12. The process of claim 9 whereinCCl₃CH₂CHCl₂ is reacted with HF to form CF₃CH═CHCl, and the fluorinationproduct comprising CF₃CH═CHCl is used as the precursor stream for (a).13. The process of claim 9 wherein CCl₃CH₂CCl₃ is reacted with HF toform CF₃CH═CCl₂ and CF₃CH₂CCl₂F and the fluorination product comprisingCF₃CH═CCl₂ and CF₃CH₂CCl₂F is used as the precursor stream for (a). 14.The process of claim 9 wherein CF₃CCl₂CF₃ is produced in (a), andCF₃CH₂CF₃ is produced in (c).
 15. A process for the manufacture ofCF₃CF═CF₂, and at least one compound selected from CF₃CH₂CF₃ andCF₃CHFCHF₂, comprising: (a) contacting a reactor feed comprisingprecursor stream of at least one compound selected from halogenatedpropanes of the formula CX₃CH₂CH_(y)X_((3−y)) and halogenated propenesof the formula CX₃CH═CH_(y)X_((2−y)), where each X is independentlyselected from Cl and F and y is 0, 1 or 2, provided that the averagefluorine content of said precursor stream is no more than 5 fluorinesubstituents per molecule, with HF and Cl₂ in a chlorofluorinationreaction zone containing a fluorination catalyst and operating at atemperature between about 150° C. and 400° C., to produce a reactionzone effluent comprising HF, HCl and a mixture of reaction products ofsaid precursor stream which contains at least one compound of theformula C₃Cl₂F₆ including CClF₂CClFCF₃ and at least one compound of theformula C₃HClF₆ including CHF₂CClFCF₃ and has an average fluorinecontent which is at least one fluorine substituent per molecule morethan the average fluorine content of the precursor stream; (b)distilling the reaction zone effluent of (a) to produce (i) alow-boiling component comprising HCl and when they are present in saidreaction zone effluent, C₃F₈, C₃C1F₇ and C₃HF₇, (ii) a hydrogenationfeed component comprising at least one compound of the formula C₃Cl₂F₆including CClF₂CClFCF₃ and at least one compound of the formula C₃HClF₆including CHF₂CClFCF₃, and (iii) an underfluorinated componentcomprising halogenated propanes containing at least one chlorinesubstituent and from one to five fluorine substituents; (c) reacting theCClF₂CClFCF₃ and CHF₂CClFCF₃ of hydrogenation feed component (ii) withhydrogen to produce a mixture comprising CF₃CF═CF₂ and CF₃CHFCHF₂; (d)recovering the CF₃CF═CF₂ from the product mixture of (c); and (e)returning the underfluorinated component (iii) to the chlorofluorinationreaction zone.
 16. The process of claim 15 wherein CCl₃CH₂CH₂Cl isreacted with HF to form CF₃CH═CH₂, and the fluorination productcomprising CF₃CH═CH₂ is used as the precursor stream for (a).
 17. Theprocess of claim 16 wherein the CCl₃CH₂CH₂Cl is reacted in a reactorwhich is free of added catalyst.
 18. The process of claim 15 whereinCCl₃CH₂CHCl₂ is reacted with HF to form CF₃CH═CHCl, and the fluorinationproduct comprising CF₃CH═CHCl is used as the precursor stream for (a).19. The process of claim 15 wherein CCl₃CH₂CCl₃ is reacted with HF toform CF₃CH═CCl₂ and CF3CH₂CCl₂F and the fluorination product comprisingCF₃CH═CCl₂ and CF₃CH₂CCl₂F is used as the precursor stream for (a). 20.The process of claim 15 wherein CF₃CCl₂CF₃ is produced in (a), andCF₃CH₂CF₃ is produced in (c).